1. Field of the Invention
The present invention relates to short range proximity sensing along a narrow strip, and more particularly to short range strip proximity sensing using a single sensor based on micro-power impulse radar MIR.
2. Description of Related Art
Very short range proximity sensing according to the prior art requires a large number of sensors distributed at close intervals in order to provide continuous perimeter coverage. If the sensor's range is one foot, for example, sensors must be placed every two feet or closer to provide seamless coverage. For many applications, like detecting the perimeter of a large display case, or the perimeter of a car, a large number of sensors would be needed.
For example, in the parent U.S. patent application entitled RANGE-GATED FIELD DISTURBANCE SENSOR WITH RANGE-SENSITIVITY COMPENSATION (IL-9514); filed Sep. 6, 1994; application number 08/300,769; now U.S. Pat. No. 5,521,600; issued May 28, 1996; a micro-power impulse radar field disturbance sensor is described. However, a number of these sensors would be required to cover a long strip or the perimeter of a large object. Similarly, other prior art sensors, such as that described in Orlowski, et al., U.S. Pat. No. 5,150,123 are suitable for detecting disturbances only in relatively small fields. Thus, in order to monitor a large perimeter, expensive security systems are required based on large numbers of sensors, or other long range sensing technologies.
Accordingly, it is desirable to provide a low cost, effective, short range proximity sensing device which is capable of use along a long line or around a large perimeter.